THE ABC has reminded its journalists to restrain themselves from campaigning in favour of same-sex marriage on social media and in their news coverage.

In an all-staff email on Thursday, seen by news.com.au, editorial policy manager Mark Maley wrote that “now that the government has announced the postal plebiscite, the focus has returned well and truly to the rights and wrongs of same-sex marriage and the changing of the Marriage Act”.

“Please remember that approximately 40 per cent of the population opposes the change and more importantly that the ABC does not have a position on the issue,” he wrote. “It is very important that we are impartial and that all perspectives are given a fair hearing and treated with respect by the ABC.

“In this charged environment I would also urge everyone to be circumspect on social media — advocating for one side or the other will make it more difficult for the ABC to be seen as impartial. The more high-profile you are the more important discretion is.”

Mr Maley added that “language is also important”.

“The preferred terminology is same-sex marriage, rather than ‘marriage equality’ or ‘gay marriage’,” he wrote, linking to the public broadcaster’s guidance on the issue.

“Some people will inevitably be offended by arguments and statements made by both sides. That cannot be avoided and we should not censor any debate conducted in good faith,” he wrote.

“However, the editorial policies also state that we should not offend our audiences without editorial justification and we should not be seen to condone or encourage prejudice and discrimination.

“To the greatest extent possible we should be facilitating a vigorous but also civil debate. If you think any content may cross the line don’t hesitate to seek advice from your manager or from me.”

In a follow-up email, ABC’s head of radio, Michael Mason, urged staff to “please remember to always be respectful, balanced and impartial”. “I’m looking forward to hearing the in-depth, quality coverage that the community relies on from ABC Radio,” he wrote. “I know we will facilitate an informative and civil debate.”

Another document being circulated among staff, written in September ahead of the original, failed plebiscite bill introduced to federal parliament, said the debate had “already thrown up some unprecedented questions”.

“Will it unleash a torrent of abusive and divisive rhetoric?” it reads. “Will it breach the anti-discrimination laws by encouraging hate speech? Will Australians of strong faith be attacked and intimidated for having their say? Why are we even having this debate at all, when most Australians want same-sex marriage legalised?”

The document lists “a few basic things” for journalists and producers to keep in mind in their coverage, including to “explore the nuance” of the discussion and not just “round up the usual suspects” to interview. It also recommends not leaning too heavily on opinion polls.

“The latest opinion polls suggest that 60 per cent of Australians support same-sex marriage and that is important and relevant information,” it says. “But polls are educated guesses rather than facts. Polls can change, polls can be wrong. The debate should be about the issues, not the numbers.”

It also warns against “overt campaigning”.

“Having a personal view on such an issue is inevitable,” it says. “As a citizen, every ABC staff member will be required to vote and so participating in the process is your right. That can include attending meetings, rallies, expressing views as an ordinary citizen.

“But overt campaigning on the issue — whether through social media or other public forums — can undermine your ability to do your job as an independent and impartial ABC program maker or journalist, so think carefully about how you participate in the process and seek advice.”

Earlier on Thursday, Liberal frontbencher Zed Seselja accused the ABC of campaigning for same-sex marriage. “We’ve seen a lot of censorship of those arguing against change in the Marriage Act, Media Watch has commented that even the ABC, who are tasked with being fair in their charter, haven’t actually been fair on this issue and haven’t equally given both sides an airing,” he told Sky News.

“Those arguing against change do have a lot of things stacked against them, virtually every media outlet is campaigning for change, the ABC has effectively been campaigning for change and there is a lot of corporate money that we’ve seen.

“I suspect we will see the ‘yes’ case out spend the ‘no’ case by probably ten to one but that doesn’t mean the Australian people won’t still make a decision that they don’t want to see the Marriage Act changed.”

It comes after Lateline host Emma Alberici opened an interview with Finance Minister Mathias Cormann earlier this week with a confronting question. “A friend of my daughter’s, a 15-year-old boy, came out as gay last week to his parents and was kicked out of home,” she said.

“Whilst you and your colleagues are bickering in your party room, aren’t you concerned about the message you send to young vulnerable gay and lesbian Australians that they won’t deserve the same treatment as other Australians?”